America's top team were firm favourites to win gold after Breezy Johnson topped the times in the morning's downhill run, but Shiffrin stuttered through her slalom and the pair finished out of the medals, in fourth.

Shiffrin and Johnson, already world champions in the discipline, had a slender lead of 0.06sec over Austria 2 but Shiffrin's World Cup form had been so good that the prospect of any other winners seemed impossible.

Shiffrin, who left Beijing without a single Olympic medal four years ago and failed to finish three of six races, was only 15th fastest down the slope in Cortina d'Ampezzo, a huge shock in her favoured discipline.

The 30-year-old has won a record 108 races on the World Cup circuit, including seven of this season's eight slalom races.

But there will be huge pressure on her for next week's slalom, the final women's alpine skiing event at this year's Olympics.

The team combined made its Olympic debut at the this year's Games, with Switzerland's Franjo von Allmen and Tanguy Nef winning the men's event on Monday.

It comprises two racers from the same nation racing a downhill and a slalom, with the fastest aggregate time earning the gold medal.

Countries are allowed to enter multiple teams in the event, with women's skiing powerhouses the USA, Switzerland, Italy and Austria each having four pairings entered on Tuesday.